Deveroite-(Ce)

Chemical formula: Ce<sup>3+</sup><sub>2</sub>((C<sub>2</sub>)<sup>6+</sup>O<sub>4</sub>)<sub>3</sub>·10H<sub>2</sub>O

Deveroite-(Ce) is a very rare, hydrated cerium oxalate, forming microscopic, colorless or white tabular crystals.

## Characteristics Deveroite-(Ce) is a hydrated cerium oxalate belonging to the humboldtine group. It occurs as extremely small, tabular or bladed crystals, rarely exceeding 0.2 mm in length. It typically forms dispersed aggregates, coatings, or appears as single, isolated crystals on the surface of the host rock. Due to its microscopic size, its visual characteristics are difficult to observe without specialized equipment. ## Physical Properties Deveroite-(Ce) crystals are characterized by a vitreous luster and are transparent. This mineral is very soft, with a Mohs hardness of approximately 2. It exhibits perfect cleavage in one direction, which is typical for its crystal structure. The density calculated from the chemical formula and unit cell parameters is 2.33 g/cm³. ## Colors and Varieties The mineral is colorless to white. No color varieties or commercial varieties are distinguished. ## History and Name The mineral is named in honor of Mr. Devero L. Jarvis (born 1961), an American mineral collector from Arizona, who discovered the first samples of this mineral. It was officially approved by the International Mineralogical Association (IMA) in 2007. The suffix -(Ce) in the name indicates the dominance of cerium in its chemical composition.

Properties

Mohs hardness
2
Luster
Vitreous
Streak
White
Density
2.33
Cleavage
Perfect on {010}
Fracture
Uneven
Transparency
Transparent
Crystal system
Monoclinic

Diagnostic features

## Identification Identification of deveroite-(Ce) is impossible without advanced laboratory techniques, such as Raman spectroscopy or X-ray diffraction (XRD). Under collector conditions, identification relies solely on a label from an analytically confirmed locality. Microscopically, characteristic, fine, colorless crystals with a tabular habit can be observed. ## Distinguishing from Similar Minerals It can be confused with other secondary oxalate minerals, such as whewellite, weddellite, or coskrenite-(Ce), which can form similar coatings. Definitive differentiation requires specialized analytical studies. ## Crystal Forms It forms very small, flattened, tabular crystals with a hexagonal or octagonal outline, often elongated in one direction, forming bladed forms. Crystals occur singly or form small, dispersed aggregates.

Geological environment

## Genesis Deveroite-(Ce) is a secondary mineral, forming in the oxidation zones of ore deposits, especially in environments rich in rare earth elements. Its formation is likely associated with the activity of microorganisms (fungi or lichens) that produce oxalic acid. This acid, reacting with primary minerals containing cerium (e.g., allanite), leads to the precipitation of deveroite-(Ce) on rock surfaces. ## Mineral Associations It co-occurs with minerals such as allanite-(Ce) (as a primary mineral), as well as other secondary oxalates like coskrenite-(Ce) and zugshunite-(Ce). ## Localities The only confirmed occurrence of this mineral in the world (type locality) is the Alpe Devero quarry in the Devero Valley, Piedmont region, Italy.

Rarity

Extremely rare

For collectors

## Quality Criteria As a "micromount" type mineral, the collector value of deveroite-(Ce) primarily depends on the confirmation of its identity by a reputable laboratory. Specimens showing well-formed, albeit microscopic, crystals, preferably in association with other rare minerals, are most highly prized. The abundance of occurrence on the rock matrix also increases the specimen's value. ## Popular Localities The only source of specimens is the type locality - the Alpe Devero quarry in Italy. Specimens from this location are highly sought after by collectors specializing in rare and "micromount" minerals.

Care and storage

## Cleaning Due to its extreme rarity, small size, and delicacy, deveroite-(Ce) specimens should generally not be cleaned mechanically or chemically. Any attempts at cleaning risk irreversible damage to the crystals. If dust removal is necessary, it can be done very carefully with a soft brush or a gentle stream of compressed air from a distance. ## What to Avoid Avoid contact with water, acids, detergents, and all chemicals. The mineral is very soft and brittle, so it should be protected from shocks, impacts, and friction. It should not be heated or exposed to ultrasound. ## Storage Specimens should be stored exclusively in specialized, sealed "micromount" boxes that protect against dust, mechanical damage, and changes in humidity. Store in stable room conditions, away from sources of vibration and direct sunlight.

Sources

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